A single sliding plate, or a so called sliding plate set, are parts of a sliding closure (sliding system, sliding gate) for the regulation/control of the outflow volume and the outflow speed of a metal melt from a metallurgic vessel, for example a ladle or a tundish.
Sliding plate systems of the named type comprise so called linear sliders and rotary sliders. They can comprise two or more plates. At least one of the plates is movable (at a linear slider: linearly movable; at a rotary slider: rotationally movable). Each plate features two main surfaces, which run parallel to each other, and at least one opening, each, which extends between the two main surfaces, so perpendicular to the main surfaces.
Through displacement of the movable plate (hereafter called sliding plate), corresponding openings of the plates can be arranged offset, partially overlapping or aligned with each other in order to adjust the mass and speed of the melt that is led through or to interrupt the stream of melt.
All plates consist of a fireproof ceramic material, which is able to resist the high temperatures of the metal melt (for example 1,500° C.). Especially during the opening and closing of the sliding closure, strong signs of corrosion show up on the fireproof material.
The EP 0 373 287 A2 describes a sliding plate, which features multiple discharge openings, so that the sliding plate can still be used when the first discharge opening is worn out, by using the second discharge opening for the regulation of the sliding closure.
Alternatively, the DE 103 24 801 A1 suggests to design the discharge openings of the sliding plates with different diameters so that depending to the use of one or the other discharge opening, more or less metal melt can flow through the control valve (the sliding closure).